To express the product of (5x - 2)(3x + 2) as a trinomial;
[tex]\begin{gathered} (5x-2)(3x+2) \\ 15x^2+10x-6x-4 \\ \text{Note that the order of expanding the parenthesis is:} \\ \lbrack5x\times3x\rbrack+\lbrack5x\times2\rbrack-\lbrack2\times3x\rbrack-\lbrack2\times2\rbrack \\ 15x^2+4x-4 \\ \text{Multiply the product by x and you have} \\ x(15x^2+4x-4) \\ 15x^3+4x^2-4x \end{gathered}[/tex]Note that a trinomial has its highest index power to the power of 3. Therefore to express the result as a trinomial (which already has its highest index power to the power of 2), you now multiply the result by x to the power of 1 (or simply x)
